response time & time-to-first-byte

Haven’t had much luck finding this in existing documentation or within this group…
My question is:
Is the response time the time-to-first-byte or time-to-last-byte?


time to last

In simulation.log, we log requestStart, requestEnd, responseStart and responseEnd.
In standard reports, we only compute response time (responseEnd - requestStart) and latency (responseStart - requestEnd).



Hello there,

[Note: Sorry to resume such an older post, but I haven’t found the info I needed on more recent topics. Please advise in case it would be better if I open a new thread instead.]

The format of simulation.log seems to have changed since the above reply.
As of today (with Gatling v2.3.0) is there a way to look at Time-To-First-Byte for the performed tests?


No, this metric is not available, and I’m not convinced it’s really useful.
Note that we now only provide response time metric in Gatling OSS.

Also, not that in FrontLine, we provide TCP connect duration and TLS handshake duration metrics, so we might easily add new ones if they make sense.


Thank you for the quick reply Stéphane.

In our use-case the TTFB is really meaningful: we are using Gatling to test some ABR flows over HTTP, and given the big size of the video chunks -few MB-, the complete Response Time is not an accurate metric of the responsiveness of the Origin Server (because the payload download time is added up).

We will have a look to the FrontLine product and the metrics provided.

Best regards,

Makes sense, thanks!
Indeed, we could quickly add it in FrontLine.